I don't recommend this, but, an eBay seller attempted it ... according to (by all that I can tell) urban lore.

Michelman said it's not the first time he has seen a business try to muzzle its critics through the use of non-disparagement clauses or legal devices to stop customers from writing negative reviews. One method he has seen is a company assigning over to itself copyright of a customer review. Earlier this year, Public Citizen represented a customer in Greenville, S.C., who was sued by an eBay seller after she gave the seller a low-star rating.